In the above-mentioned technical field, a patent literature 1 discloses technology, wherein, when a client requests to upload video data for browsing on a site, a verifying server verifies the video data with video data already registered by a registrant to determine whether the video data should be uploaded or not (refer to [FIG. 1]). Moreover, the patent literature 1 discloses that it is possible to realize high speed verifying process by use of thumbnail images in verifying by the verifying server and furthermore by use of a group of still pictures which are extracted optionally or randomly in verifying.